JP2011145575A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact image forming apparatus capable of maintaining high degree of possibility of cleaning, high service life, and high reliability inexpensively without complicating its configuration. <P>SOLUTION: The image forming apparatus calculates image area (rate) and average image area (rate) based on the input printing information (image area or the like) and controls lubricant application time and application of lubricant being the operation in lubricant application mode based on the results of computation while performing input and output of the information into/from a recorder. That is, the apparatus obtains a printing order or an interval between papers or average image area and the number of printed papers of an image forming unit after completion of printing, substitutes thus obtained average image area for an expression for calculating amount of reverse transfer toner to obtain a value for determining execution of lubricant application mode, and determines the presence of lubricant application and application time from the number of printed papers. If it is determined based on both of thus obtained values that there is lubricant application, a priority is given to that having longer application time. After applying lubricant in accordance with the predetermined conditions, the average image area and the number of printed papers are reset to 0. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printing machine, a facsimile machine, or a multifunction machine using the electrophotographic system.

  Electrophotographic image formation uses a photoconductive phenomenon to form an electrostatic charge image (electrostatic latent image) on an image carrier, and charged electrostatic particles (toner) colored on the electrostatic latent image. Is a process of making a visible image by adhering with an electrostatic force.

  In this electrophotographic image forming apparatus, various components such as waxes, fluorine resins (polytetrafluoroethylene, polyvinylidene fluoride, etc.) and higher fatty acid metal salts (zinc stearate) are used as the main components of the image carrier and intermediate transfer member. Etc.) as a lubricant. This technique is used to solve a problem that occurs in an electrophotographic cleaning process, that is, a process in which toner and impurities remaining on an image carrier and an intermediate transfer belt are scraped off by a cleaning brush or a cleaning blade.

  The solution to the problem by applying the lubricant is to improve the cleaning property of the toner from the surface of the image carrier. By applying the lubricant to the surface, the coefficient of friction of the surface is reduced, and deposits attached to the surface can be easily removed from the surface. That is, the transfer residual toner remaining on the image carrier or the intermediate transfer belt and the toner image on the intermediate transfer member formed by the upstream image forming unit cannot be transferred onto the final recording material such as paper. The reverse transfer toner transferred onto the image carrier when passing through the image carrier of the image forming unit can be easily removed. In particular, the reverse transfer toner contains a weakly charged toner with a small charge amount and a reversely charged toner with a reverse charge polarity, so that the electrostatic adhesion to the image carrier is strong, and the average particle size of the toner Since it contains a large amount of small particle size toner, its physical adhesion to the image carrier is strong, making it difficult to clean, and the amount of reverse transfer toner increases in the downstream image forming unit. There is a problem that defects tend to occur. Also from such a technical background, it is considered that improvement of the cleaning property by using a lubricant will become a more important technology in the future.

  Further, as a solution to the problems caused by applying the lubricant, it is to prevent oxidative deterioration due to discharge on the surface of the image carrier. In order to form an electrostatic charge image (electrostatic latent image) on the image carrier, it is necessary to uniformly charge the surface of the image carrier by charging means. As a specific charging means, in recent years, there is a means for applying a high voltage to the charging roller member to directly discharge the image bearing member for charging. However, since the image carrier is directly discharged, the surface of the image carrier deteriorates. In particular, in a so-called non-contact charging roller system in which the charging roller member is not brought into contact with the image carrier, it is necessary to apply an AC voltage to the roller member, and it has been found that the surface of the image carrier is likely to deteriorate. It has been clarified that the deteriorated surface of the image bearing member is easily worn by mechanical rubbing with a cleaning brush or a cleaning blade which is a cleaning member.

  Therefore, the technique of applying a lubricant to the surface of the image carrier is an important technique for reducing damage to the image carrier due to electric discharge.

  In general, the lubricant is supplied to the surface of the image carrier in a small amount in the form of powder. As a specific method, the lubricant formed on the block is scraped off by a coating means such as a brush. There is a method of applying powdered lubricant held in a brush in contact with an image carrier.

  However, when a plurality of image forming units such as a color image forming apparatus are provided, it is difficult to reduce the size of the image forming apparatus if a solid molded lubricant is arranged for each image forming unit. Furthermore, a plurality of solid lubricants and a mechanism for coating are required, which increases the cost. In addition, generally used higher fatty acid metal salts have poor lubricity due to the effect of charging, and toner passes through the cleaning member, resulting in poor cleaning. Further, when the amount of fatty acid metal salt applied is excessive, the fatty acid metal salt itself flies and adheres to the charging member, causing contamination of the charging member. On the other hand, if the coating amount is insufficient, the role of protecting the photoconductor cannot be achieved, leading to the occurrence of filming. For this reason, tuning of the lubricant application amount is important.

  In order to solve these problems, Patent Document 1 (Japanese Patent Laid-Open No. 2008-276103) and Patent Document 2 (Japanese Patent Laid-Open No. 2008-276083) use a lubricant from an intermediate transfer member to carry a plurality of images. By reducing the surface friction coefficient of the body, a configuration aiming at cost reduction and miniaturization has been proposed in which the lubricant application device does not need to be arranged in a plurality of image forming units. In Patent Document 1, a plurality of image carriers and an intermediate transfer are respectively brought into contact with and separated from each other, and a powdery lubricant on the intermediate transfer member is selectively supplied to the image carrier. However, when such a contact / separation mechanism is provided, the apparatus configuration becomes complicated, which is disadvantageous in terms of cost reduction and space saving. In Patent Document 2, the powdery lubricant on the intermediate transfer member is selectively supplied to a plurality of image carriers by an electrostatic force between the image carrier and the intermediate transfer member. However, in this configuration, even when it is not desired to supply the lubricant onto the image carrier, when the powdery lubricant passes through the contact portion between the image carrier and the intermediate transfer member, a physical pressure such as contact pressure is used. It has been found that the amount of lubricant supplied to the image carrier on the downstream side is reduced by the force, and the amount of lubricant supplied to the downstream image carrier is reduced. In Patent Document 3 (Japanese Patent Laid-Open No. 2009-186610), the use of at least a hydrophobic organic compound, inorganic fine particles, and an inorganic lubricant can be used for a long period of time to prevent toner cleaning slipping. However, since the image forming apparatus includes a plurality of image forming units due to the structure including the image forming unit including the lubricant application device, there is a limit to cost reduction and size reduction.

  Therefore, in the present invention, when the powdery lubricant applied to the intermediate transfer member is supplied to the image carrier, the intermediate transfer member is driven in the reverse direction so that the downstream image forming unit can be formed without a complicated configuration. Therefore, it is possible to supply an image forming apparatus that can supply a sufficient amount of lubricant for suppressing defective cleaning, and that is small, low-cost, and does not cause cleaning defects over a long period of time without complicating the configuration. Objective.

  The present invention relates to a plurality of image forming units each including at least an image carrier, a developing device, a charging device, and a cleaning device, and intermediate transfer for transferring the image formed by the image forming unit to a recording material. In the image forming apparatus comprising a body and a lubricant application device disposed on the intermediate transfer body, the powder lubricant applied to the intermediate transfer body by the lubricant application device is used as the image of the image forming unit. Lubricant application mode operation control means for controlling the operation of the lubricant application mode for entering the carrier is provided, and the lubricant application mode operation control means drives the intermediate transfer member in the reverse direction with respect to the drive direction at the time of image formation. It is characterized by performing control.

  In the image forming apparatus of the present invention, the lubricant provided in the lubricant applying apparatus may include at least a hydrophobic organic compound, inorganic fine particles, and an inorganic lubricant.

  An image forming apparatus according to the present invention includes an image area calculating unit that calculates an area of an imaged image, and an image area rate calculating unit that calculates an image area rate that is a ratio of the area of the imaged image to a recording material. And from the image area ratio calculated by the image area calculation means or the image area ratio calculated by the image area calculation means, the image area ratio average of the image area ratio calculated by the image area calculation means Average value calculating means for calculating a value, and print information for controlling the operation of the lubricant application mode by the lubricant application mode operation control means as an image area, an image area ratio, an average image area, and an average image An area ratio, or an image area, an image area ratio, an average image area, and a calculated value calculated from the average image area ratio may be used.

  The image forming apparatus of the present invention includes a print number counting unit that counts the number of images formed, and print information for controlling the operation of the lubricant application mode by the lubricant application mode operation control unit. Further, the number of printed sheets or a calculated value calculated from the number of printed sheets may be used.

  The image forming apparatus of the present invention includes a driving unit that can operate at a plurality of printing speeds, and further includes printing as print information for controlling the operation of the lubricant application mode by the lubricant application mode operation control unit. A configuration using speed may be employed.

  The image forming apparatus of the present invention uses an image area ratio and an average image area ratio as print information for controlling the operation of the lubricant application mode by the lubricant application mode operation control means, and further, the recording material size May be used.

  In the image forming apparatus of the present invention, the lubricant application mode is controlled by the lubricant application mode operation control means, and the lubricant application time for the lubricant application device to apply the lubricant to the image carrier is set as the control target. It can be set as the structure.

  The image forming apparatus of the present invention includes a transfer unit that transfers a toner image on the intermediate transfer member to a recording material, and a cleaning unit that cleans the intermediate transfer member. The transfer unit and the cleaning unit are connected to the intermediate unit. A configuration may be adopted in which the transfer member is disposed apart from the transfer member.

  The image forming apparatus of the present invention may have a configuration in which the lubricant application mode is performed before, after, or during non-image formation with the image forming unit.

  According to the present invention, by supplying the lubricant applied to the intermediate transfer member to the image carrier, the surface friction coefficient of the image carrier is lowered, and in the case of a configuration including a plurality of image forming units, all the image forming units This eliminates the need for a lubricant applicator. In addition, in a device that uses a lubricant to enter the image forming unit via the intermediate transfer member, the intermediate transfer member is driven in reverse so that the downstream image forming unit does not have a complicated cleaning. It is possible to provide an image forming apparatus that can supply a sufficient amount of lubricant for suppression, that is small in size and low in cost, and that does not cause a cleaning defect over a long period of time without complicating the apparatus configuration.

It is a figure which shows the structure of a color image forming apparatus (at the time of image formation). It is a figure which shows the structure of an image formation unit (at the time of image formation). It is a figure showing composition of a lubricant application device (at the time of image formation). It is an enlarged view of the contact part of an intermediate transfer body and a brush member (at the time of image formation). FIG. 6 is a diagram showing a series of operations in which a powder lubricant is transferred to a photosensitive drum by a transfer member and thinned by a blade member that is a cleaning device (at the time of image formation). FIG. 3 is an enlarged view in which a photosensitive drum and a cleaning member as a cleaning device are in contact (at the time of image formation). It is a figure which shows the structure of a color image forming apparatus (at the time of lubricant application mode execution). FIG. 5 is a diagram showing a series of operations in which a powder lubricant is transferred to a photosensitive drum by a transfer member and thinned by a blade member that is a cleaning device (when a lubricant application mode is executed). FIG. 4 is an enlarged view in which a photosensitive drum and a cleaning member as a cleaning device are in contact (when a lubricant application mode is executed). It is the schematic of the apparatus comprised by a calculating means, a memory | storage means, a control means, etc. It is a flowchart which shows an example of the control method of the lubricant application mode which performs execution judgment based on an image area and the number of printed sheets. 6 is a flowchart illustrating an example of a lubricant application mode control method for performing execution determination based on an image area ratio, the number of printed sheets, and a recording material size. 6 is a flowchart illustrating an example of a control method of a lubricant application mode in which execution determination is performed based on an image area ratio, the number of printed sheets, a recording material size, and a printing speed.

  The cleaning failure that occurs in the image forming unit of the image forming apparatus is a reverse transfer in which the toner image on the intermediate transfer member formed by the upstream image forming unit is transferred when passing through the image carrier of the downstream image forming unit. It has been found that when a large amount of toner enters the cleaning device, it tends to occur. This is because the reverse transfer toner contains a weakly charged toner with a small charge amount and a reversely charged toner with a reverse charge polarity, so that the electrostatic adhesion to the image carrier is strong and the toner average particle size is small. This is thought to be due to the fact that since the toner contains a large amount of toner having a particle size, the physical adhesion to the image carrier is strong, making it difficult to perform cleaning. In particular, when a plurality of image forming units are provided, the amount of reverse transfer toner increases as the downstream image forming unit increases, and cleaning defects are more likely to occur. In order to suppress poor cleaning, it is effective to reduce the surface friction coefficient of the image carrier.

  For this reason, in the conventional image forming apparatus, the lubricant is applied to the image carrier by mounting the lubricant in the image forming unit to suppress the cleaning failure. However, mounting the lubricant on the image forming unit is disadvantageous in terms of installation space and cost.

  Therefore, the present invention reduces the surface friction coefficient of the image carrier by supplying the lubricant applied to the intermediate transfer member to the image carrier, so that all image forming units are configured in the case of a configuration including a plurality of image forming units. Eliminates the need to place a lubricant applicator in the unit. Further, in the method of causing the lubricant to enter the image forming unit via the intermediate transfer member, a large amount of lubricant is taken in the upstream image forming unit, and the amount of reverse transfer toner is large, so that cleaning failure tends to occur. Although there was a problem that the amount of lubricant supplied to the downstream image forming unit was reduced, the downstream image forming unit was poorly cleaned by driving the intermediate transfer member in the reverse direction without complicating the structure. A sufficient amount of lubricant for suppression can be supplied. As a result, it is possible to prevent a cleaning failure from occurring over a long period of time without being complicated in size and cost.

  In other words, the present invention provides at least an image carrier and a developing device in order to provide a long-life and high-reliability image forming apparatus that is small, low-cost, and has a long cleaning margin without complicating the configuration. A plurality of image forming units including a charging device and a cleaning device, an intermediate transfer member that transfers toner formed by the image forming unit and conveys the image to a recording material, and a lubricant disposed on the intermediate transfer member In an image forming apparatus provided with a coating device, operation in a lubricant coating mode in which a powdery lubricant applied to an intermediate transfer member by a lubricant coating device disposed on the intermediate transfer member rushes into an image carrier of an image forming unit Is performed by driving the intermediate transfer member in the reverse direction with respect to the drive direction at the time of image formation. In the present invention, by rotating the intermediate transfer member in the reverse direction, a sufficient amount of lubricant is supplied to the downstream image forming unit to suppress the cleaning failure without a complicated configuration. It is possible to prevent defective cleaning over a long period of time without complicating the configuration.

  According to the present invention, in order to provide a long-life and high-reliability image forming apparatus having a high cleaning margin over a long period of time, the lubricant provided in the lubricant coating apparatus is at least a hydrophobic organic compound (A). And inorganic fine particles (B) and an inorganic lubricant (C). The lubricant containing the hydrophobic organic compound (A), the inorganic fine particles (B), and the inorganic lubricant (C) is excellent in lubricity, and does not wear the cleaning member. To prevent. In the present invention, a lubricant containing a hydrophobic organic compound (A), inorganic fine particles (B), and an inorganic lubricant (C) is applied to an image carrier via an intermediate transfer member, thereby producing zinc stearate. The image bearing member and the intermediate transfer member are prevented from being poorly cleaned more effectively than the conventional lubricant.

  In addition, the present invention provides an image area calculation for calculating the area of an image formed in order to provide a long-life and high-reliability image forming apparatus that has a long cleaning time and high cleaning margin regardless of the printed image. Means, an image area ratio calculating means for calculating an image area ratio which is a ratio of the image area to the recording material, and an image area or image area ratio which is an average value from the image area or image area ratio of the image formed. In an image forming apparatus provided with an average image area (rate) calculation means to calculate, as print information for controlling the operation of the lubricant application mode, image area, image area ratio, average image area, average image area ratio, or An arithmetic value calculated from the image area, the image area ratio, the average image area, and the average image area ratio is used. Cleaning failure is likely to occur when a large amount of reverse transfer toner enters the cleaning device, and the amount of reverse transfer toner increases as the image area and image area ratio increase (higher). When there are many large (high) prints, it is necessary to frequently perform the lubricant application mode as compared with the case where there are few large (high) prints. The present invention uses, as print information for controlling the operation in the lubricant application mode, an image area (rate), an average image area (rate), or a calculated value calculated from the image area (rate) or average image area (rate). Thus, it is possible to prevent the image carrier from being poorly cleaned due to the printed image area (rate), and thereby to provide an image forming apparatus that does not cause a cleaning defect over a long period of time regardless of the printed image. .

  In addition, the present invention provides a printed sheet count that counts the number of formed images in order to provide a long-life and highly reliable image forming apparatus that has a long cleaning time and high cleaning margin regardless of the number of printed sheets. In the image forming apparatus including the means, the number of printed sheets or a calculated value calculated from the number of printed sheets is used as print information for controlling the operation in the lubricant application mode. The cleaning failure is likely to occur when the reverse transfer toner accumulates in the cleaning device. For this reason, it is necessary to carry out the lubricant application mode at regular intervals. According to the present invention, it is possible to prevent defective cleaning of the image carrier due to the number of printed sheets by using the number of printed sheets or a calculated value calculated from the number of printed sheets as print information for controlling the operation of the lubricant application mode. it can. Accordingly, there is provided an image forming apparatus in which cleaning failure does not occur over a long period of time regardless of the number of printed sheets.

  The present invention also provides a lubricant in an image forming apparatus having a plurality of printing speeds in order to provide a long-life, high-reliability image forming apparatus that has a long cleaning time and high cleaning margin regardless of the printing speed. The printing speed is used as printing information for controlling the operation in the application mode. In order to suppress the cleaning failure, a lubricant is applied to the surface of the image carrier in order to reduce the surface friction coefficient of the image carrier. The applied lubricant deteriorates due to a charging hazard by a charging device. In an image forming apparatus having a plurality of printing speeds, the slower the printing speed, the longer the time required for the image carrier to receive a charging hazard in a single printing, so the lower the printing speed, the higher the surface friction coefficient on the image carrier. Prone. For this reason, when there are many prints with a low printing speed, it is necessary to frequently execute the lubricant application mode as compared with a case where the printing speed is high. In the present invention, by using the printing speed as printing information for controlling the operation in the lubricant application mode, it is possible to prevent the image carrier from being poorly cleaned due to the printing speed. Accordingly, there is provided an image forming apparatus in which cleaning failure does not occur over a long period of time regardless of the printing speed.

  In addition, the present invention provides printing for controlling the operation of the lubricant application mode in order to provide a long-life and high-reliability image forming apparatus that has a long cleaning margin regardless of the recording material size and has a high cleaning margin. In the image forming apparatus using the image area ratio and the average image area ratio as information, the recording material size is used as print information for controlling the operation in the lubricant application mode. A cleaning failure tends to occur when a large amount of reverse transfer toner enters the cleaning device. The amount of reverse transfer toner increases as the image area ratio increases. Even if the image area ratio is the same value, the image area varies depending on the size of the recording material. Even if the image area ratio is the same, the amount of reverse transfer toner increases when the image area increases, and it is necessary to frequently execute the lubricant application mode. In the present invention, the printing information for controlling the operation of the lubricant application mode is determined by adding the recording material size to the image area ratio or the average image area ratio, thereby causing poor image carrier cleaning due to the printed image area ratio. Can be prevented. Accordingly, there is provided an image forming apparatus that does not cause a cleaning defect over a long period of time regardless of the recording material size.

  Further, the present invention provides a long-life and high-reliability image forming apparatus in which cleaning failure and abnormal images are unlikely to occur over a long period of time. Is the lubricant application time for applying the lubricant to the image carrier. If the amount of lubricant applied is insufficient, the margin of the cleaning device decreases, and if the amount of lubricant applied is too large, the lubricant that has passed through the cleaning device contaminates the charging device and an abnormal image such as density unevenness occurs. Therefore, it is necessary to apply an appropriate amount for applying the lubricant. In the present invention, by controlling the coating time, the amount of lubricant applied to the image carrier can be made appropriate, and the excess and deficiency of the amount of lubricant applied to the image carrier can be eliminated. Provided is an image forming apparatus that is less likely to cause defective cleaning or abnormal images over a longer period of time.

  The present invention also provides a transfer unit for transferring a toner image on an intermediate transfer member to a recording material in order to provide a small-sized, low-cost, long-term, high-cleaning margin, long-life, highly-reliable image forming apparatus. In the image forming apparatus including the cleaning unit for cleaning the intermediate transfer member, the transfer unit and the cleaning unit are separated from the intermediate transfer member. When the transfer unit and the cleaning device are brought into contact with each other when the intermediate transfer member is driven in reverse in the lubricant application mode, the transfer unit is contaminated by transferring the powdery lubricant applied to the intermediate transfer member to the transfer unit. Or the cleaning device cleans the amount of lubricant supplied to the image forming unit. For this reason, it is necessary to separate the transfer unit and the cleaning device in the lubricant application mode. In the present invention, by separating the transfer unit and the cleaning device in the lubricant application mode, the lubricant can be efficiently supplied to the image forming unit without contaminating the transfer unit, and the lubricant provided in the lubricant application device The amount of can be reduced. The present invention provides a long-life and high-reliability image forming apparatus that is smaller in size, lower in cost, and has a long cleaning margin over a long period of time.

  According to the present invention, in order to provide an image forming apparatus that does not cause a cleaning defect over a long period of time, the lubricant application mode is executed at the time of non-image formation such as before image formation, after image formation, and between image formation. . Ideally, the lubricant application mode is performed when there is no deposit such as toner on the intermediate transfer member. This is because if the deposit is present on the intermediate transfer member, the deposit will contaminate the lubricant application device, resulting in uneven application of the lubricant and a decrease in coating efficiency. For this reason, it is desirable that the lubricant application mode be performed when no image is formed on the intermediate transfer body without any deposits. The present invention prevents the lubricant application device from being contaminated by deposits on the intermediate transfer body by performing the lubricant application mode at the time of non-image formation, thereby reducing uneven application of the lubricant and lowering of the application efficiency. Can be suppressed. Accordingly, an image forming apparatus that does not cause a cleaning defect over a long period of time is provided.

  Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the illustrated image forming apparatus.

An example of a color image forming apparatus that is an object of the present invention will be described.
FIG. 1 is a diagram illustrating the operation of the color image forming apparatus during image formation. The color image forming apparatus has a plurality of image forming units (a, b, c, d), an intermediate transfer member e, and a lubricant applying device f. The image forming units (a, b, c, d) are filled with black, cyan, magenta, and yellow toners to form full-color images. However, the order of the toner colors of the image forming units is not limited to this. It does not have to be.

  Each color toner formed by a plurality of image forming units (a, b, c, d) is superimposed on an intermediate transfer member e that rotates in the direction of arrow B in the figure, and is formed of a plurality of color toners. It becomes a pattern. A transfer unit 19 is disposed on the intermediate transfer member e, and a toner image on the intermediate transfer member e is transferred to a recording material P such as paper that moves in the direction of arrow C in the figure by applying a transfer bias to the transfer unit 19. Is done.

  The transfer unit 19 can use a transfer member such as an elastic roller member, and is brought into contact with the surface of the intermediate transfer member e with a predetermined pressing force, thereby forming a transfer nip between the transfer member and the intermediate transfer member e. . A toner image on the surface of the intermediate transfer member e is formed by a transfer electric field formed by applying a transfer bias having a polarity opposite to that of the toner from a transfer bias power source to the transfer member while the recording material P is sandwiched between the transfer nips. Transfer onto the recording material P. The recording material P onto which the toner image has been transferred in this manner is conveyed to a fixing device (not shown), where the toner image is fixed and then discharged outside the image apparatus.

FIG. 2 is a diagram illustrating the operation of the image forming unit during image formation.
The image forming unit (a, b, c, d) includes a photosensitive drum 1 as an image carrier that rotates in the direction of arrow A in the drawing. As the photosensitive drum 1, a photosensitive layer made of an organic photosensitive member is formed on the outer peripheral surface of an aluminum substrate, and the drum surface layer is made of polycarbonate.

  Around the photosensitive drum 1, a charging device 2 as a charging unit, a developing device 3 as a developing unit, and a cleaning device 4 as a cleaning unit are arranged.

  The developing device 3 performs development by attaching toner to the electrostatic latent image formed on the surface of the photosensitive drum 1. The developing device 3 includes a developing roller 5 as a developer carrying member and a toner supply roller 6 that supplies toner to the developing roller 5. Furthermore, a toner filling part and a waste toner collecting and holding space part 7 are provided in the upper part of the developing device.

  The toner filled in the toner filling unit 7 in advance is replenished to the lower portion of the developing device 3 by its own weight, and the replenished toner is supplied to the rotating toner supply roller 6, and the toner is supplied to the developing roller 5 and held by the toner supply roller 6. The The developing roller 5 rotates while carrying the toner on the surface thereof, thereby conveying the toner to a developing region facing the photosensitive drum 1. A developing bias is applied to the developing roller 5 from a developing bias power source. As a result, a potential difference is generated between the potential on the surface of the developing roller 5 and the potential on the electrostatic latent image portion on the surface of the photosensitive drum 1 in the developing region, and the toner is affected by the developing electric field formed by the potential difference. Adheres to the electrostatic latent image. As a result, the electrostatic latent image on the photosensitive drum 1 becomes a toner image.

  In the present embodiment, a description is given using a one-component developer composed only of toner that does not use a carrier. In particular, the developing device using a two-component developer in which a carrier and a toner are mixed may be used.

  The charging device 2 uniformly charges the surface of the photosensitive drum 1. The charging device 2 is arranged such that a charging member is brought into contact with the surface of the photosensitive drum 1 or a small gap is provided with respect to the surface of the photosensitive drum 1 and a charging bias is applied thereto to thereby apply the charging bias to the surface. Are uniformly charged to a desired polarity and a desired potential. As the charging member, a charging roller made of an elastic body can be used.

  The cleaning device 4 removes untransferred toner remaining on the surface of the photosensitive drum 1 without being transferred from the surface of the photosensitive drum 1. As the cleaning device 4, a cleaning blade member for scraping and removing the transfer residual toner on the surface of the photosensitive drum 1 is used. As the cleaning blade member, a polyurethane blade member attached to a metal support is used, and the contact method with the photosensitive drum 1 is made to contact the counter drum with respect to the rotation direction A of the photosensitive drum 1. As for the cleaning blade member, not only toner removal from the photosensitive drum 1, but also paper dust when using paper as the recording material P, discharge products generated by discharging the photosensitive drum 1 by the charging device 2, and toner are added. It also has a function of removing impurities such as additives from the photosensitive drum 1.

  The toner removed from the photosensitive drum 1 is transported to the end of the image forming unit by the toner transport member 8 and transported to the waste toner collecting and holding space section 7. The toner removed at this time is not used as a developing toner again when a one-component developer is used, but can be used again as a developing toner when a two-component developer is used.

  Regarding the toner, it is preferable to use a spherical toner having a circularity of 0.98 or more in order to improve the image quality. Here, the “circularity” is an average circularity measured by a flow type particle image analyzer FPIA-2000 (trade name, manufactured by Toa Medical Electronics Co., Ltd.). Specifically, in 100 to 150 (ml) of water from which impure solids have been removed in advance in a container, 0.1 to 0.5 (ml) of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant, Further, about 0.1 to 0.5 (g) of a measurement sample (toner) is added. Thereafter, the suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the dispersion concentration is set to 3000 to 1 (10,000 pieces / μl). Set and measure toner shape and distribution. As the spherical toner, it is possible to use an irregularly shaped toner (pulverized toner) whose shape is distorted by a pulverization method that has been widely used in the past, which has been spheroidized by heat treatment, or a toner manufactured by a polymerization method. The manufacturing method is not limited.

FIG. 3 is a diagram illustrating the operation of the lubricant application device f during image formation.
The lubricant application device f has a roller-shaped brush member 9 that rotates in the direction of arrow E in the drawing, a solid lubricant 10, and a pressing member 11 that presses the solid lubricant 10 against the roller-shaped brush member 9. Yes. Further, the lubricant application device f has a blade member 14 as a cleaning unit for removing residual toner and impurities on the surface of the intermediate transfer member e. The intermediate transfer member e moves in the direction of arrow B in the figure as the driving roller 15 rotates in the direction of arrow D in the figure.

FIG. 4 is an enlarged view of a contact portion between the intermediate transfer member e and the brush member 9 at the time of image formation.
The brush member 9 is installed so as to come into contact with the solid lubricant 10, and the solid lubricant 10 is scraped off at the edge of the tip of the brush bristles as the brush member 9 rotates in the direction of arrow E. At this time, the powdery lubricant adheres to and is held on the surface of the brush fiber constituting the brush member 9 and is applied to the intermediate transfer member e. The brush member 9 rotates in the direction of arrow E, and the intermediate transfer member e rotates in the direction of arrow B. That is, the rotation direction of the brush member 9 and the intermediate transfer member e rotates in the same direction and comes into contact with the counter direction.

The effect which makes two members the same rotation direction is demonstrated.
The brush member 9 is configured to come into contact with the intermediate transfer member e at a constant interval (biting amount), so that a nip is formed between the brush member 9 and the intermediate transfer member e. In this nip portion, the bristle of the brush member 9 falls in a direction different from the rotation direction E of the brush member 9. Since the brush member 9 that has fallen at the nip portion is rotated by the brush member 9, it is eventually released at the nip portion outlet side, and the brush hair tries to return to its original state. At this time, the bristle moves violently in the brush rotation direction due to the restoring force. (It will move by the repulsive force.) Due to this repulsive force, the powdery lubricant held on the brush member 9 leaves the brush member 9 and flies to be applied to the intermediate transfer member e.

  Here, when the rotation direction of the intermediate transfer member e and the brush member 9 is the same direction, the powdered lubricant applied by flying to the intermediate transfer member e on the outlet side of the brush nip is again applied to the brush member 9 and the intermediate transfer member e. Therefore, the leveling effect by the brush member 9 is exhibited, and uneven application of the powdery lubricant on the surface of the intermediate transfer member e is less likely to occur. Therefore, the uneven application of the lubricant can be improved by setting the rotation direction of the intermediate transfer member e and the brush member 9 to the same direction.

  The roller-shaped brush member 9 is made of resin fibers such as nylon, rayon, acrylic, vinylon, polyester, and vinyl chloride. If necessary, a conductive material obtained by mixing a conductive agent such as carbon with the above-described resin fibers. Fiber may be used. Further, the roller-shaped brush member 9 is a brush in which brush hair having a length in the range of 0.2 to 20 (mm), preferably 0.5 to 10 (mm) is planted on a base cloth made of metal. What was comprised by winding on a spiral can be used. When the length of the brush hair is 20 (mm) or longer, the inclination angle in the reverse direction of the brush body decreases due to repeated rubbing with the solid lubricant 10 and the brush member 9 along with the operation time of the intermediate transfer member e, and the fall hair In addition, the scraping property of the solid lubricant 10 and the coating property of the lubricant to the intermediate transfer member e are deteriorated. When the length of the brush hair is 0.2 (mm) or less, the physical force on the solid lubricant 10 is insufficient. Therefore, it is preferable to set it in the range of 0.2 to 20 (mm), preferably 0.5 to 10 (mm).

  The powder lubricant 16 uniformly applied to the intermediate transfer member e is conveyed in the direction of arrow B in the figure, and is eventually conveyed to the transfer section of each image forming unit (a, b, c, d).

  FIG. 5 is a diagram showing a series of operations in which the powder lubricant 17 is transferred to the photosensitive drum 1 during image formation and is thinned by the blade member which is the cleaning device 4.

  In this embodiment, since the photosensitive drum 1 is negatively charged by the charging unit 2 and further developed to the photosensitive drum 1 by the developing device 3 using the negatively charged toner, the transfer member 18 has a positive value. By applying voltage or current, the toner on the photosensitive drum 1 is transferred to the intermediate transfer member e. On the other hand, the powdery lubricant 16 supplied from the lubricant application device f is also present on the intermediate transfer member e, and the powdery lubricant 16 passes through the contact portion between the intermediate transfer member e and the photosensitive drum 1. At this time, it is transferred onto the photosensitive drum 1 by the contact pressure. For the transfer of the powder lubricant 17 onto the photosensitive drum 1, the action of an electric field generated by applying a bias to the transfer roller 18 may be used.

  FIG. 6 is an enlarged view in which the photosensitive drum 1 and a cleaning member as the cleaning device 4 are in contact with each other during image formation. The cleaning member removes residual toner and impurities on the photosensitive drum 1. In the present invention, the cleaning member also serves as a means for thinning the powdery lubricant 17. As described above, the cleaning member is a rubber member that is a strip-shaped elastic body. By using the rubber member, a certain amount of the photosensitive drum 1 can be bitten (pressed in) and brought into contact, and the cleaning member and the photosensitive drum 1 can form a nip. Like the toner, the powdery lubricant 17 stays in the nip portion of the cleaning member, and passes through the surface of the photosensitive drum 1 as a thin film lubricant 20 by the pressure from the cleaning member.

  The finer the powdery lubricant applied on the intermediate transfer member e by the lubricant application device f, the thinner the film can be formed on the surface of the photosensitive drum 1 by the cleaning member. As the lubricant film progresses, the lubricant can fully exhibit its lubricity. On the contrary, if the lubricant enters the nip portion of the cleaning member in a coarse powder state, an excess of lubricant remaining on the photosensitive drum 1 will remain, and eventually the nip portion will be powdered. It slips through and adheres to the photosensitive drum 1, which causes contamination of the charging means. Further, unevenness of the lubricating film on the surface of the photosensitive drum 1 occurs, and adversely affects development, transfer, and cleaning.

The operation in the lubricant application mode will be described below.
FIG. 7 is a diagram illustrating the operation of the color image forming apparatus in the lubricant application mode. In the lubricant application mode, the intermediate transfer member e rotates in the direction indicated by the arrow Y in the direction opposite to that at the time of image formation, whereby powder lubrication applied on the intermediate transfer member e by the lubricant application device f. The agent enters the contact portion between the image forming unit d and the intermediate transfer member e. A part of the pulverized powdery lubricant is transferred onto the image carrier in the image forming unit d, and the remaining powdery lubricant rushes into the contact portion between the image forming unit c and the intermediate transfer member e. Similarly, the powdery lubricant enters the image forming unit b and the image forming unit a. At this time, the powdery lubricant applied to the intermediate transfer member e is transferred to the transfer unit 19 so that the transfer unit is contaminated or cleaned by the blade member 14 provided in the lubricant application device f. In order to prevent this, the transfer unit 19 and the blade member 14 are separated from the intermediate transfer member e.

  In addition, in the lubricant application mode, the intermediate transfer member e is driven in the direction opposite to the driving direction at the time of image formation. Therefore, if there is a deposit on the intermediate transfer member e, the deposit is cleaned by the blade member 14. Before that, the brush member 9 enters the brush member 9 for applying the lubricant to the intermediate transfer member e, and the brush member 9 is contaminated by the deposits. As a result, there are concerns about the occurrence of uneven application of lubricant and a decrease in application efficiency. For this reason, the lubricant application mode is performed during non-image formation such as before image formation, after image formation, and between image formation.

  FIG. 8 is a diagram showing a series of operations in which the powder lubricant 17 is transferred to the photosensitive drum 1 and is thinned by the blade member which is the cleaning device 4 in the lubricant application mode. The powdery lubricant 16 supplied from the lubricant application device f is present on the intermediate transfer member e, and when the powdery lubricant 16 passes through the contact portion between the intermediate transfer member e and the photosensitive drum 1. It is transferred onto the photosensitive drum 1 by the contact pressure. For the transfer of the powder lubricant 17 onto the photosensitive drum 1, the action of an electric field generated by applying a bias to the transfer roller 18 may be used. At this time, in order to prevent contamination of the powdery lubricant to the charging unit 2, the bias application to the charging unit 2 is performed with a bias having the same polarity as the charging polarity of the powdery lubricant, or the bias application is performed. It is desirable not to.

  FIG. 9 is an enlarged view in which the photosensitive drum 1 and the cleaning member as the cleaning device 4 are in contact with each other in the lubricant application mode. The photosensitive drum 1 rotates in the direction of arrow Z in the figure, and the powdery lubricant 16 of the photosensitive drum 1 enters a nip portion formed by the cleaning member and the photosensitive drum 1. The pulverized powder lubricant 17 stays in the nip portion of the cleaning member like the toner, and passes through the surface of the photosensitive drum 1 as a thin film lubricant 20 by the pressure from the cleaning member.

  The finer the powdery lubricant applied on the intermediate transfer member e by the lubricant application device f, the thinner the film can be formed on the surface of the photosensitive drum 1 by the cleaning member. As the lubricant film progresses, the lubricant can fully exhibit its lubricity.

  The solid lubricant 10 that can be used in this embodiment includes at least a hydrophobic organic compound (A), inorganic fine particles (B), and an inorganic lubricant (C), and has sufficient lubricity.

  Examples of the hydrophobic organic compound (A) include hydrocarbons classified into aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic saturated hydrocarbons, alicyclic unsaturated hydrocarbons and aromatic hydrocarbons. In addition to the above, polytetrafluoroethylene (PTFE), polyperfluoroalkyl ether (PFA), perfluoroethylene-perfluoropropylene copolymer (FEP), polyvinylidene fluoride (PVdF), ethylene-tetrafluoroethylene copolymer Examples thereof include fluorine resins such as polymers (ETFE) and fluorine waxes, silicone resins such as polymethyl silicone and polymethyl phenyl silicone, and silicone waxes. Typical fatty acids from which the above fatty acid metal salts and stable hydrophobic metal salts are extracted include caproic acid, caprylic acid, enanthylic acid, pelargonic acid, undecylic acid, lauric acid, tridecoic acid, myristylic acid, Palmitic acid, margaric acid, stearic acid, non-cyclic acid, arachidic acid, behenic acid, styringic acid, palmitoleic acid, oleic acid, petricerinic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, ricanin There are acids, valinal acid, gadoleic acid, arachidonic acid, whale oil and mixtures thereof. Typical stable metal salts of fatty acids include barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate , Zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, palmitate Aluminum oxide, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricinoleate, cadmium ricinoleate and mixtures thereof There is a thing, but is not limited to this. Moreover, you may mix and use these.

  The inorganic lubricant (C) refers to a substance that cleaves and lubricates itself or causes internal slip. Examples of this include, but are not limited to, mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, and graphite. Boron nitride, for example, has hexagonal mesh surfaces with tightly intermingled atoms and a wide gap between them, and only the weak van der Waals force connects the layers, so that the layers are easily cleaved and lubricated. .

  On the other hand, the inorganic fine particles (B) refer to particles that are sandwiched between objects and serve as a roller but do not cause internal slip or cleavage by the substance itself. Examples of this include metal oxides such as silica, tin oxide, zinc oxide, titanium oxide, alumina, zirconium oxide, indium oxide, antimony oxide, bismuth oxide, calcium oxide, antimony-doped tin oxide, tin-doped indium oxide. Products, metal fluorides such as tin fluoride, calcium fluoride, and aluminum fluoride, potassium titanate, and the like, but are not limited thereto. Moreover, you may use these in mixture.

Here, a control method of the lubricant application mode in the embodiment of the present invention will be described with reference to FIG.
As the application mode control means for executing the control of the lubricant application mode, for example, a calculation means 42, a storage means 41, and a control means that are usually used in an image forming apparatus and are provided for performing image formation process control. A device composed of 40 or the like can be assigned the function. Alternatively, a dedicated device composed of calculation means, storage means, control means, etc. may be provided. In any case, the lubricant application mode operates in cooperation with an apparatus that performs image formation process control and inputs / outputs information. The calculation means 42 is a calculation means for calculating the image area (rate) and the average image area (rate) based on the input print information (image area, printing speed, recording material size), and counts the number of printed sheets. It is also a means for counting and is performed while inputting / outputting information to / from the recording means 41, and based on the calculation result of the calculation means 42, the controller 40 performs the lubricant application time and the lubricant application which are operations in the lubricant application mode. The image forming unit to be executed is controlled.

<Example 1 of control procedure of lubricant application mode>
This will be described with reference to FIG. After the print command, the interval between sheets, or after the end of printing (step 1), the average image area (AY, AM, AC) of each Y, M, C image forming unit and the number N of prints so far are acquired (step 2) ). The acquired average image area (AY, AM, AC) is substituted into an arithmetic expression based on the expression for calculating the reverse transfer toner amount, and the lubricant application mode execution determination value Z is acquired (step 3). The presence / absence of lubricant application and the application time are determined from the determination value Z obtained by the above calculation and the number of printed sheets N so far. In this embodiment, “Z> 45 → 20 s”, “Z> 35 → 15 s”, “A> 25 → 10 s”, “Z> 15 → 5 s”, “Z> 10 → 3 s”, “Z> 5”. → 0s ”,“ N> 100 → 10s ”, and“ N ≦ 100 → 0s ”. When both lubricants Z and N are coated with lubricant, priority is given to the longer coating time (step 4). After applying the lubricant according to the above-described conditions (step 5), the average image area and the number of printed sheets are reset to 0 (step 6).

<Example 2 of control procedure of lubricant application mode>
This will be described with reference to FIG. After the print command, the interval between sheets, or after the end of printing (step 1), the average image area ratio (RY, RM, RC) of each Y, M, C image forming unit and the number N of prints so far are obtained (step). 2). The acquired average image area ratio (RY, RM, RC) is substituted into an arithmetic expression based on an expression for calculating the reverse transfer toner amount, and an arithmetic value Z1 is acquired (step 3). Further, the lubricant application mode execution determination value Z is obtained by multiplying the calculated value Z1 by a coefficient X1 for calculating the image area depending on the recording material size (step 4). The presence / absence of lubricant application and the application time are determined from the determination value Z obtained by the above calculation and the number of printed sheets N so far (step 5). In this embodiment, “Z> 45 → 20 s”, “Z> 35 → 15 s”, “A> 25 → 10 s”, “Z> 15 → 5 s”, “Z> 10 → 3 s”, “Z> 5”. → 0s ”,“ N> 100 → 10s ”, and“ N ≦ 100 → 0s ”. When both lubricants Z and N are coated with lubricant, the one with the longer coating time is given priority. After applying the lubricant according to the above-described conditions (step 6), the average image area and the number of printed sheets are reset to 0 (step 7).

<Example 3 of control procedure of lubricant application mode>
This will be described with reference to FIG. After the print command, the interval between sheets, or after the end of printing (step 1), the average image area ratio (RY, RM, RC) of each Y, M, C image forming unit and the number N of prints so far are obtained (step). 2). The acquired average image area ratio (RY, RM, RC) is substituted into an arithmetic expression based on an expression for calculating the reverse transfer toner amount, and an arithmetic value Z1 is acquired (step 3). Further, the calculation value Z1 is multiplied by a coefficient X1 for calculating the image area according to the recording material size to obtain the calculation value Z2 (step 4). Furthermore, the lubricant application mode execution determination value Z is obtained by multiplying the calculated value Z2 by a coefficient X2 in consideration of the contribution to the reverse transfer toner amount due to the printing speed (step 5). The presence / absence of lubricant application and the application time are determined from the determination value Z obtained by the above calculation and the number of printed sheets N so far (step 6). In this embodiment, “Z> 45 → 20 s”, “Z> 35 → 15 s”, “A> 25 → 10 s”, “Z> 15 → 5 s”, “Z> 10 → 3 s”, “Z> 5”. → 0s ”,“ N> 100 → 10s ”, and“ N ≦ 100 → 0s ”. When both lubricants Z and N are coated with lubricant, the one with the longer coating time is given priority. After applying the lubricant according to the above-described conditions (step 7), the average image area and the number of printed sheets are reset to 0 (step 8).

a, b, c, d: image forming unit e: intermediate transfer member f: lubricant applying device P: recording material 1: photosensitive drum 2: charging device 3: developing device 4: cleaning device 5: developing roller 6: toner Supply roller 7: Toner filling portion and waste toner collecting and holding space portion 8: Toner conveying member 9: Brush member 10: Solid lubricant 11: Pressing member 14: Blade member 15: Drive roller 16: Powder lubricant 18 (a, b, c, d): transfer roller 19: transfer unit 20: thin film lubricant 40: control means 41: storage means 42: calculation means

Japanese Patent No. 4238193 JP 2008-195507 A JP 2009-186610 A

Claims (9)

A plurality of image forming units comprising at least an image carrier, a developing device, a charging device, and a cleaning device;
An intermediate transfer member for transferring the image formed by the image forming unit and conveying the image to a recording material;
A lubricant application device disposed on the intermediate transfer member;
In an image forming apparatus comprising:
Lubricant application mode operation control means for controlling the operation of the lubricant application mode in which the powdery lubricant applied to the intermediate transfer member by the lubricant application device enters the image carrier of the image forming unit. ,
The lubricant application mode operation control means performs control by driving the intermediate transfer member in the reverse direction with respect to the drive direction at the time of image formation.
An image forming apparatus. The image forming apparatus according to claim 1.
The lubricant provided in the lubricant application device includes at least a hydrophobic organic compound, inorganic fine particles, and an inorganic lubricant.
An image forming apparatus. The image forming apparatus according to claim 1, wherein
Image area calculating means for calculating the area of the image formed;
Image area ratio calculating means for calculating an image area ratio that is a ratio of the area of the imaged image to the recording material;
From the area of the imaged image or the image area ratio calculated by the image area calculation unit, the area average value of the imaged image or the image area ratio average value of the image area ratio calculated by the image area calculation unit is calculated. An average value calculating means for calculating,
As printing information for controlling the operation of the lubricant application mode by the lubricant application mode operation control means,
Image area, image area ratio, average image area and average image area ratio,
Or
Image area, image area rate, calculated value calculated from average image area and average image area rate,
Either
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 3,
As a printing information for controlling the operation of the lubricant application mode by the lubricant application mode operation control means, further comprising a print number counting means for counting the number of images formed,
Use the number of printed sheets or a calculated value calculated from the number of printed sheets.
An image forming apparatus. 5. The image forming apparatus according to claim 1, wherein:
Provided with driving means that can operate at a plurality of printing speeds,
As printing information for controlling the operation of the lubricant application mode by the lubricant application mode operation control means, further using a printing speed,
An image forming apparatus. The image forming apparatus according to any one of claims 3 to 5,
As the printing information for controlling the operation of the lubricant application mode by the lubricant application mode operation control means, the image area ratio, the average image area ratio is used, and further, the recording material size is used.
An image forming apparatus. The image forming apparatus according to any one of claims 1 to 6,
The lubricant application mode operation control means by the lubricant application mode operation control means is the lubricant application time during which the lubricant application device applies the lubricant to the image carrier.
An image forming apparatus. The image forming apparatus according to claim 1,
A transfer unit for transferring the toner image on the intermediate transfer member to a recording material;
A cleaning unit for cleaning the intermediate transfer member,
The transfer unit and the cleaning unit are arranged apart from the intermediate transfer member,
An image forming apparatus. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the lubricant application mode is performed before, after, or during non-image formation by the image forming unit.